I enjoy new audio
experiences and as technology marches on--seemingly
one tick ahead of time--there is an ever-continuous
stream of new tech toys being developed. They come
to market at a dizzying speed and if you blink, you
miss something really good. I have missed a lot over
the last few years; lately it has been the USB audio
revolution.

This past year I decided
that the next logical step in my own digital audio
evolution to be high resolution capable audio
playback. Having audio served up hot from a computer
on my mind, I asked PFO Editor Dave Clark to find
one of the many new USB DACs on the market for me to
experience. He found a very cool one: The Human
Audio Muto HD DAC. Of course, no DAC is of any value
to a computer without an interface, so bring on the
Tabla, Human Audio’s Dual Asynchronous USB to
Sony/Phillips Digital Converter. Both units were
designed and built by Human Audio Ltd. of Hungary
and are represented in the U.S. by True Audiophile
of Portland, Oregon.

The Past, Present, and
Future

I have long admired the
beauty and potential of high resolution audio. I
tried SACD in its infancy, but it just couldn't
trump computer-based Lossless playback in my
listening room. Yes, as stupid as it may sound, I
dumped a particularly fine Sony SA-777ES SACD player
in favor of the convenience and very good sound of
the Squeezebox 2 streaming .WAV and ALAC files. Now
however, with Hi Res audio maturing and all genres
of titles (not just the 52nd remastering of Kind of
Blue) are becoming available from music download
sites around the globe, it is time for me to add it
to my audio arsenal. The few titles I own have been
downloaded from HDTracks
http://www.hdtracks.com/ as they seem to have
the largest selection of music I enjoy and they are
adding more titles every day. While downloading Hi
Res is a seriously cool development, I am embracing
it slowly to protect the kitty. It is easy to
download music… Waaaaay too easy. It can be an
expensive venture to willy-nilly download music at
3am.

As we audiophiles are
wont to say, "Sorry about your wallet!"

My reference Red Wine
Audio modified Squeezebox 2 and Bel Canto DAC 2 make
an excellent digital front end, but even as the
battery powered RWA SB2 performs to a level well
beyond what its humble plastic case would suggest,
it will not decode the higher bit rate and sampling
rates of high resolution files. In addition to the
SB2, I own an M-Audio USB Fastrack Pro that I use to
digitize vinyl. The Fastrack Pro is 24b/192k
capable, uses ASIO drivers and sounds good, but has
been too finicky for me to use as an everyday
playback device. I am also enjoying a Halide Designs
Bridge (on loan) to play files up to 24 bit/96kHz.
The Bridge is totally plug and play and sounds great
without computer muss or driver fuss.

Like the Halide Designs
Bridge, the Human Audio Tabla utilizes USB power
from the computer, but unlike the Halide, this power
is used to charge the Tabla's two internal
batteries. Rather than firmware drivers, the Tabla
utilizes a licensed version of the M2Tech (Hiface)
USB 2.0 driver. I downloaded the Windows 7- 64-bit
version (it is available in many OS configurations
for both PC and Mac) and it loaded up without drama
of any sort. As recommended by my newly installed J
River Media Center playback software, I set the
audio output option for WASAPI-Event Style
http://wiki.jriver.com/index.php/WASAPI and
connected the Tabla to a USB 2.0 port on my laptop
with a standard-issue 6 foot USB cable. The computer
recognized the Tabla almost immediately and was
ready for connection to the DAC.

In addition to sending
his personal Tabla and a well-traveled, fully
broken-in Muto HD for a 30 day evaluation, Gary
Alpern of True Audiophile, also sent me a Revelation
Audio Labs .5 meter BNC to BNC digital cable. This
cable was designed by Revelation Audio Labs in
concert with Mr. Alpern expressly for
interconnection of the Tabla>Muto. Fit and finish of
the cable is first rate and the length works
perfectly to set the two units adjacent to each
other. The BNC connectors are excellent. My own
Belden 1506A homebrew cable is very good and while I
didn't have much time to compare the two, the RAL
cable added a good measure of clarity over the
Belden. While not inexpensive, it is quite
obviously, a very nice complement to the Human Audio
gear. I must admit I probably need to upgrade…

…All together now
readers, “Sorry about your wallet Gary!”

[Sidebar: I recently
purchased the very nice (and cheap) Asus K55A laptop
with Gen 3, i-5 core processor, 4 gigs of RAM and a
SATA hard drive running Windows 7-64 bit OS to use
as my audio server. I paired it with a 1 Terabyte
Seagate USB 3.0 portable external hard drive for
audio file storage as well as J River Media Center
Version 17 for playback software. While I wish I had
bumped up the budget for a backlit keyboard, I am
more than satisfied with my new server, especially
in light of the overall cost. In the future, I will
add more RAM, perhaps a SSD hard drive for the OS
and some type of remote control. (A Surface tablet
would be nice. Are you reading this Microsoft?). I
am still debating when and if to upgrade to Windows
8, but my gut tells me waiting is the best option
for the short term. ]

The Specs!

Rather than trying to
describe specific design information, with Gary
Alpern’s permission, I have included the
specifications and a portion of the narrative on the
Tabla, Muto and RAL cable from the True Audiophile
website:

The Muto HD DAC*

…Features include twin
LiFePO4 batteries with at least 12 hours operation
time. HD DAC up to 24bit / 192kHz with two
selectable digital (S/PDIF) inputs which are
configurable 75 ohm BNC-BNC, BNC-RCA or RCA-RCA. The
analog outputs are RCA. The whole charging process
is automated. The recharging starts when the unit is
switched-off or in case of switched-on and the level
of batteries reaches the low state. The Muto has a
unique and discrete analog output stage with
"Class-A" operation in order to give the most
realistic musical experience for the audience.

Internal batteries:
LiFePO4 high-grade cells with long (more than 5yrs)
lifetime without any memory effect

The Tabla*

…Based on the Human
Audio philosophy this device is purely battery
powered with 2 built-in high-grade
Lithium-Iron-Phosphate (LiFePO4) cells. Each one
runs separate operations. One for the USB and one
for the converter circuity. This separate is what
provides incredible blackness and giant soundstage,
making the presentation organic and liquid. These
are no mere batteries. These batteries were
originally created for the electric car industry and
have an internal resistance of .002 Ohms. There is
even a
video of one of these batteries, which are the
size of a large AA battery, starting a car.
Batteries are rated to last 8 years.

The charging is fully
automatc without any external device since the Tabla
uses the USB power for charging purpose during idle.
You do nothing. When its not playing its charging.
With up to 18 hours of runtime and nearly impossible
to run out of battery life during any normal
listening. Even if by some chance you ran it 24
hours the most that happens is the green light goes
to yellow telling you its now running off USB buss
power. We do suggest letting it charge overnight but
you will not have to worry about it interrupting
your listening.

Tabla provides ultimate
audio performance using these built-in batteries
selected for the lowest ripple and the least noise
output performance, a very advanced ripple smoothing
technology in engineered into the Tabla when using
the USB power while the battery is being silently
reloaded, ultra-low jitter (3 ppm) discrete onboard
clocks for 44.1kHz and 48kHz multiples, a
specialized pulse transformer on its real 75 Ohm BNC
output and of course one of the best USB-Audio
algorithm available on the market (developed by
M2Tech).

*Complete information
regarding the referenced equipment may be found on
the True Audiophile and Human Audio websites.

My Experience

I plugged the Muto's
small wall wart power supply into to the nearest
receptacle to charge its internal batteries. The
"wart" is very small (allowing other items to plug
in next to it!) and has a green LED to let you know
it is powered up. As noted, the Tabla and Muto both
utilize two Lithium iron phosphate (LiFePO4)
batteries per unit--good for 12+hours of playing
time. I can say that in my experience with the Human
gear, the batteries performed without incident or
issue of any kind. The wall wart automatically
charges the batteries so there is little for the
user to worry about. A simple on-off toggle switch
on the back turns the unit on and there are LED's on
the front that show battery condition. Digital input
1 & 2, signal lock and when the DAC is decoding a
frequency higher than 44.1 kHz. Whether by design or
accident, the stylish Lexan faceplates of both units
refract the LED of its current state around the edge
of the face, which of course looks understatedly
cool. The battery power supplies in both units are
designed to minimize ripple and other power nasties,
supplying constant, clean power. The 1.25 V Output
Voltage is a bit lower than any DAC I have used to
date.

The Tabla and Muto both
worked flawlessly during the entirety of my 30 day
evaluation. The Muto's low output voltage required a
tweak of the volume knob on the Slagle Auto former
Volume Control to reach a volume level similar to my
reference's 2.0V output, but a positive to that was
the gain of an additional few steps of useable
volume control. While I believe the Muto’s lower
output voltage may have scaled back large dynamic
swings a smidge, the sound emanating from the Omega
Super Alnico's was clear, precise, and melodic.

It should be noted that
the observation regarding dynamics may not be
altogether due to the Muto. I have noticed this
difference to a lesser degree with all my gear when
using the passive Slagle AVC. The upside of course
is a purity and directness that is a hallmark of
many passive designs. While dynamics might suffer
just slightly, the battery powered chain of Asus
K55A laptop>Tabla>Muto HD driving the Slagle
provides a deathly quiet, blacker than black
background. In fact, it is the quietest I have ever
heard my system.

My computer-based music
collection consists mainly of 16-bit/44.1kHz Redbook
CD's ripped to Apple Lossless (ALAC) .WAV or FLAC
format. Mixed in are smatterings of MP3's and Hi-Res
FLAC files, a few 24-bit/192kHz, but most in 24-bit/96kHz. To gauge inner resolution, micro and
macro dynamics, I listened to the FLAC-ripped CD
layer from the hybrid SACD of Fritz Reiner
conducting the Chicago Symphony's 1960 recording of
Rimsky-Korsakoff's masterwork Scheherazade. Large
scale dynamics do not seem to be quite as good as my DAC 2, yet blackness between notes is impressive
allowing excellent dynamic contrast. Perhaps this
sounds contradictory, but as I have found with my
own battery-powered RWA SB2, there is unquestionably
something to be said for the quiet nature of a
battery powered playback chain. While large scale
swings may suffer without serious amperage behind
them, on the micro level, dynamics are excellent.
The single driver Omega Super Alnico's are fine
speakers, but perhaps not the last word in
untangling complex music. On the other hand, their
tone and ability to reproduce dynamic contrast is
really quite wonderful. And as expected, tonal
shadings, especially violin, were beautiful and I
was quite taken by the Omega's improved handling of
the busy parts when the untangling was reconstructed
by the Muto. Combined with the beautiful tone,
texture and cohesive nature of my system, this
classical masterpiece held my rapt attention and was
a thoroughly unforgettable listening experience in
which my entire system shined.

While I would be
negligent not to exploit well recorded material to
evaluate gear, it was not the only music I fed the
Muto. I listened to tunes I have loved for years;
some of which are not even close to audiophile
recordings. Yes, Sade, The Rolling Stones, Weather
Report, Stevie Wonder, America, Allison Krauss,
Passport, Johnny Cash... A veritable smorgasbord of
rock, jazz, roots, R&B, and blues. Throughout my
time with the Muto, I continually noted how easy it
was to quit listening for "hi-fi" qualities and just
enjoy the music. There is a balance to the sound of
these components that is natural, non-fatiguing and
well, human. (You knew it was coming didn’t you?)
Clearly this has a lot to do with my whole system
and it should be duly noted that this relaxed nature
is one I value highly in audio equipment. I
certainly don't want every recording to sound the
same—no "Rose Colored Glasses Effect" for me—but
wanting to hear what differentiates recordings
doesn't mean “Ruthlessly revealing” either. Human
Audio must feel the same way, as the Tabla/Muto gave
me the beauty and the beast without ear-bleeding
stridency or glossing over poor recordings.

Tone and timbre were
very good as well. Being intimately familiar with
the brassy burnished tone of live saxophones, I
always listen intently to their tone in recordings.
One of my go-to selections for horns is the 2000
Grammy Album of the Year, Steely Dan's Two Against
Nature. On TAN, an abundance of great players strut
their saxy stuff and as I listened, all sounded
great and correct. Check out Chris Potter's solo on
West of Hollywood and you'll see what I mean; great
tone indeed!

While there doesn't seem
to be an aggressive bone in the Muto, there is
attack when demanded and decay when required. I
would not say it was a particular strength of this
DAC, but it was good in my system. The top end is a
wonderful mix of delicate and wispy; the low end
always tuneful, authoritative when necessary, but
never overpowering. The midrange is lovely and
smooth, yet complex and perhaps ever so slightly
recessed in the upper reaches. This would seem a
calculated voicing by Human Audio and while it works
to great effect on 90 percent of what I listened to,
however there were times when I thought the Muto
could use just a tad more energy/edge up
top—especially on serious guitar-driven hard rock.
That said, all in all, from top to bottom, balance
seems to be a prime directive for the sound of this DAC. It is hard to argue against the results.
Listening to the Tabla/Muto through my system is
much like looking at a woven tapestry. There is
beautiful layering to the music, yet it is presented
as a whole picture. And while I am certainly able to
pick out individual details when I desire to do so,
most of the time it is the whole that touches me.

The Muto has that
terrific "Pace, Rhythm, And Timing" (PRAT) thing too
and while difficult to describe, once heard, it is
not easily forgotten. This seems to be a particular
strength of the Muto and one that only a handful of
DACs I've heard share. The Tabla/Muto did not throw
the huge, 3D, airy stage presence that I have heard
at times with the Bel Canto. And while the Omega’s
completely disappeared on many recordings, there
were no sounds bouncing around the room, or huge
images of players on a stage. It is a more
controlled staging, certainly an intimate one in my
system. The Muto places instruments and voices
between the speakers in good stead and depth is
good, but sound rarely travels forward of, or
outside the plane of the speakers. From some of the
reports I have read, this is a strength of the Tabla;
so had I more time to play with set up I might have
found the magic, but as it was, I never quite got it
locked in. Make no mistake; imaging and staging are
very good, just not "incredibly spectacular".
Therefore, those of you who put heavy emphasis on
spatial audio trickery need to hear these components
in your own system and judge accordingly—you may be
surprised with the outcome. If I ever get another
crack at them, I may find a different outcome as
well.

A disclaimer of sorts:

Remembering that this is
first and foremost an experience article and not a
“traditional” review, I may go about evaluating a
component a bit differently than others and even
differently from my reviews of years past. Yes, I
pepper my writing with a few "audiophile" buzz words
and the structure may evoke review, but my goal as
stated is to use a piece of gear and report back my
findings. How well did it work? Did I enjoy it? Did
it sound good or bad in my system?

Well, here are the
answers: The Tabla and Muto worked very well, not
one issue and extremely simple operation to boot. I
absolutely enjoyed them 100% and they sounded so
good in my system that I hated to send them home. It
is unfortunate for me that I had such a short window
of opportunity with the Human Audio gear. Thirty
days is not a great deal of time to evaluate and
compare digital components, especially in light of
the fact that writing about audio is not my
full-time job and I (as we all do) have many other
demands on my time. But being the Human's were in
such high demand, I was unable to keep them any
longer. The result was that I spent much more time
just listening to the Tabla/Muto/Revelation gear in
my system and much less comparing them to other
components I own. I was unable to spend any
meaningful time with my active preamp, so I make no
comments as to the differences between it and my AVC.
Additionally, I never played with the Muto as a
standalone DAC, or with the big McCormack solid
state amp in the chain. Lastly, as alluded to
earlier in this missive, I do not own many hi
resolution files. So I focused primarily on my
existing library of music as played through my new
Laptop and software. Again, all these are new to me.
I don't necessarily like to write about any
component with so many new additions to my system,
but hey, I can't use a USB interface without the
associated gear!

An Observation

It seems that high end
digital audio converters have reached a state where
they are all very good and the differences between
them are small. Yet power supply, DAC chip type, and
overall design topology will, more often than not,
cause differences worth noting. This is the case
here as well. When compared directly with the Bel
Canto DAC 2 + Tabla, there were in fact, many
similarities and the differences were minute in many
respects. I did find some noticeable differences.
The Muto had a much lower noise floor and created a
wonderful space around the notes that was lacking in
the DAC 2. The Bel Canto holds the edge in large
scale dynamics and seemed to be the most resolving
of fine detail, but it lost out to the Muto's
wonderful handling of complex musical passages.

The Wrap

The single most
important observation I take from my short time with
the Human Audio Tabla USB Converter and Muto HD DAC
is that they are unfailingly consistent. From top to
bottom they just sounded right and if they did coat
the music in a rosy glow, I didn't hear it. They are
small, good looking, simple to use and are at the
lower end of the high-end audio cost spectrum. I
could easily live with them long term as my USB
playback chain. The Tabla and Muto HD have been back
in the hands of True Audiophile for some time and I
am feeling separation anxiety. I am...Really. Of
course, that is only human. Highly recommended for
your audition.